


Weak Spot

by Aki_Kaminari



Category: IDOLiSH7 (Video Game)
Genre: Blow Jobs, M/M, Sibling Incest, Teasing, Threesome - M/M/M
Language: English
Status: Completed
Published: 2016-09-21
Updated: 2016-09-21
Packaged: 2018-08-16 11:53:15
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,442
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8101414
Author URL: https://archiveofourown.org/users/Aki_Kaminari/pseuds/Aki_Kaminari
Summary: Yamato just wants to relax on his day off.  Thanks to a certain pair of twins, that doesn't happen.





	

**Author's Note:**

> This fic was born to ~~indulge in~~ accomplish two things at once—I wanted a Nanase Sandwich, and I wanted anything with Yamato. As much as I would have liked to have picked Iori, that would have ended up with Riku in the middle.  
>  There are minor mentions of ioriku, but it's not featured in this fic and thus not included in the tags.  
> I am WEAK to yamariku and it's such a pure ship, and here I am tainting it with smut. Good job, self.  
> This fic is un-beta'd, so please point out any mistakes. It's also the first time I've _finished_ writing smut, so. This is new.

As he walked down the hall to the kitchen, Yamato let the towel fall down from his head and hang over his shoulders.  His hair was still a little bit damp, but it was good enough.  The recording session for a drama he was in had ended rather late the previous night, and he hadn’t had the energy to even draw a bath afterwards.  Morning—he checked the clock and yep, 11:02 was still morning—showers were a little weird, but that was much better than nothing.  Besides, it was his day off, so it wouldn’t mess up his schedule any.

Riku had been washing the dishes, but perked up at the sound of the fridge opening.  “Ah, Yamato-san, you’re awake!  Good morning.”

There was a hiss and a pop, and Yamato flashed a grin at Riku over his can of beer.  It probably wasn’t the best thing to have right away in the morning, but habits were habits.  Even if it was just a shower instead of a bath, the humid atmosphere still triggered the routine.  “Morning,” he greeted as he shuffled through the fridge for a quick snack.

“Sorry, I didn’t hear you get up or I would have made you breakfast.  You were still completely unconscious half an hour ago,” Riku explained as he dried off a plate.

Yamato waved a hand dismissively.  “Nah, don’t worry about it.  Onii-san should be the one doing the spoiling around here.”

Riku snorted and shifted his weight from one foot to the other.  “I don’t think I’d call slightly burnt omurice “spoiling” anyone.”

The smirk on Yamato’s face was half from the conversation and half because Tamaki had left one of his puddings out in the open.  Hey, it wasn’t Yamato’s fault the chocolate kind was delicious.  “It is if you feed it to me.”  He mimed being fed with an imaginary fork.

Now Riku was laughing.  “What’s with that?  I don’t even do that with Iori; he’d probably get mad.”

“Probably,” Yamato agreed, though he was sure the kid would secretly like it.  But speaking of whom… “You’re not with Ichi today?”

The head tilt that Riku did was comparable to a puppy.  “Oh, that’s right, you weren’t here when that came up yesterday.  Exams are soon, so Iori insisted on making Tamaki spend the day studying at the library with him.”

Yamato wasn’t sure who to feel sorry for.  “That sounds rough,” he said simply.  The thought of needing to go out and bury their noses in textbooks all day made Yamato glad that his high school days were behind him.  Riku just shrugged.

“I offered to go with and help, but Iori was all, like,” Riku forced a serious frown onto his face, “Nanase-san, you should not have to worry about our studies, as someone who has already graduated.  Please rest at home on your day off.  I believe my help will be more than sufficient for Yotsuba-san.”

It was decidedly a very good thing that the pudding was still unopened, because Yamato’s burst of laughter at Riku’s impersonation made the jar tip over as he set it on the table.  He quelled his laughter just long enough to pull out a chair and sit down.  “That was spot-on!  You should teach MEZZO” better impersonations.  Trust me, I’ve seen it.”

The grin on Riku’s face was cut short by the doorbell.  He wasn’t expecting anyone, and received a shrug when he voiced the same to Yamato, so he bounded over to the door.  Yamato leaned back in the chair and took another sip of his beer as Riku opened the door. “Good morning, how can I—” 

If the pause wasn’t enough to make Yamato whirl around, the exclamation of “Ten-nii!?” definitely was.  There was a single moment of…shock? Disbelief?  But then the force with which Riku flung himself at Ten for a hug almost knocked them both over.

“Kujou?” Yamato inquired.  His face was carefully blank, but his tone was skeptical.  “Why are you here?”

With a catlike glint in his eyes, Ten parted from Riku and sauntered over to the table.  “I came over to play.”

Yamato didn’t look impressed.  “Suspicious.”  His distrust of TRIGGER’s center wasn’t nearly as blatant or as strong as Iori’s, but his desire to not have Riku hurt any more made up for it.  They had been getting along better recently, and Yamato felt that Ten _did_ genuinely care about Riku, but it was complicated.  Actually, complicated might have been too simple of a word.

Though Ten’s smile looked nothing but genuine to Riku, to anyone else—or at least to Yamato—it was positively impish.  So was the mock look of offense to that single word.  “What, I can’t want to spend some time with my adorable little brother~?”  Whatever thought or reply Yamato would have had was completely destroyed when Ten leaned down and blew into his left ear.

“Ahaha!  Yamato-san made a weird noise!” Riku exclaimed gleefully.  He dashed over to Yamato and blew into the other ear.  Yamato’s posture immediately stiffened up, and his spine pressed firmly against the back of the chair.  He couldn’t have known that his next words would seal his fate.

“O-oi, Riku…Onii-san’s weak there, so…”

A thoughtful hum from Ten was the only warning before a steady stream of air ghosted over his left ear again.  And he wasn’t sure if Ten and Riku had shared a look while he was reeling or if they had some kind of weird synchronicity thing going on, but Riku’s breath at his right resumed at almost the exact same time.  It tickled, and he squirmed, and—

“Hey!  No biting!” Yamato protested loudly.  Ten’s soft giggle and murmur of “ _so~rry_ ” was irksome.  The physical manifestation of this “apology” was something warm and wet over the same spot that had just been nibbled on.  He jerked further upright in the chair, and Ten’s hands came to rest on his shoulders.

“No running away,” he purred in that same teasing tone.  “Let’s play a while.  Right, Riku?”

All things considered, while this kind of behavior wasn’t _that_ surprising coming from Ten, nothing in the world could have prepared Yamato for Riku hoisting one leg up to _sit on his lap_ to prevent him from going anywhere.  He wasn’t used to not being the one in control of situations like this (whether the twins knew what they were doing or not) and it was disconcerting.  He could see Riku’s grin in his peripheral vision.  The redhead seemed to be having fun.  Decidedly, Kujou Ten was a bad influence.

The torture continued.  He had long since felt the heat creeping up his face all the way from his neck.  The sensation prickled and mixed in with the involuntary shudders he was trying to suppress.  How much actual time had passed was a mystery, but to Yamato, who was trying very hard to not make any more “weird noises,” it felt like ages.  Against the comparatively quiet cacophony of inhales and exhales, any sound that he did make was too loud.  The occasional touch of Ten’s mouth was indisputably intentional, but it was the rarer accidental (it _had_ to be accidental, Yamato told himself) brush of Riku’s lips, as light as a feather, that got his heart pounding.  To be honest, Yamato wasn’t sure what he could feel more of—the breaths against his ears or his own heartbeat in them.

He was making a point to sit as far back in the chair as possible and lean forward slightly, so that Riku would end up closer to his knees than his lap.  He was already going to have a difficult time looking Riku in the face once the siblings tired of their game, so he didn’t need his own body’s reactions to make things, _ahem_ , harder.

After a particularly bad attempt to stifle a moan, Riku giggled.  The sound resulted in a _worse_ attempt at being silent.  Lips moved against his skin as the redhead spoke.  “Yamato-san, does it feel good?”

It was at that moment that Yamato realized there was no such thing as the good twin/evil twin stereotype.  These two were both devils.

The feel of Riku’s tongue was the breaking point.  Yamato leaned further forward so that Riku’s back pressed against the edge of the table.  “Oi,” he started.  They locked eyes, and Yamato wanted to say something—anything—more, but the words wouldn’t come out.  What was there to say in this situation?  All of this was going too far, too fast, and his head felt like it was spinning from the absurdity of it all.  If it was anyone else—just Ten, for example—he would have snapped at them to cut it out long ago.  But Riku…he couldn’t say no to Riku.  There was something about IDOLiSH7’s center that made Yamato want to spoil and indulge him.

“Are you doing this on purpose?” Yamato said slowly.  The playfully satisfied expression that Riku wore weakened Yamato’s resolve further.  “Is it okay?” 

Half-lidded eyes and a slight forward tilt of Riku’s head was the barest indication of a nod as he whispered “If it’s with one of the other members, it’s alright.”  While the statement was just that—a statement—from Ten’s point of view, Yamato acknowledged it as a quote.  His self-control broke, and Yamato closed the rest of the distance as their mouths met.  The kiss was brief; ended by a huff from Ten.  Yamato raised an eyebrow at TRIGGER’s center as if to ask if there was a problem.

However, Riku interrupted any further interaction.  “Is that what beer tastes like?  It’s…kinda gross.”

Yamato wondered about whether it was appropriate to laugh but couldn’t help himself.

Ten stood up straight and put his hands on his hips.  “That’s no good, giving alcohol to a minor,” he scolded.  The pudding on the table caught his attention, and he popped the top off to scoop out a spoonful.  “Here, be good and say “ah” for me~”

“…I don’t want to be treated like a kid by you,” is what Yamato would have said, but he only got the first few syllables out before he got a mouthful of pudding.  Riku laughed openly at Yamato’s annoyed expression.

That same look just spurred Ten on further.  “Don’t make such an awful face.  Maybe I should help you more…?”  Ten took a bite of the pudding for himself, relishing the sweet flavor.  When he took another, he didn’t swallow—but instead locked lips with Yamato and passed it between them.  The viscous dessert made their tongues even more slick, which caused contact to be quick and fleeting.  Ten was satisfied once Yamato swallowed, and pulled away licking his own lips.  Yamato had not initially noticed Ten’s hand on his thigh, but definitely noticed once it was gone.

“You missed some,” Riku piped up, and reached to wipe a bit from the corner of Ten’s mouth.  Ten captured the hand when it touched his face and sucked the small dot of pudding from Riku’s finger.  “Te…n-…nii…?”  His voice faltered, and he swallowed hard at the feeling of Ten’s tongue against his skin.

Interesting.

“Did you want to help feed _Yamato-san_ too?” Ten asked, and Yamato didn’t know what to think of the imitation of Riku’s way of addressing him.  Yamato’s mind further blanked when Ten took another spoonful and purred, “Don’t spill any,” before once again popping it into his own mouth.  He stroked Riku’s cheek to coax him closer.  Riku only had a second to anticipate what happened next.

Yamato kissing him, Riku mused, was mostly expected with how the situation had escalated.  _Ten-nii_ kissing him was not.  Though, it wasn’t as if he was about to complain.  There was a moment’s hesitation on Ten’s part that felt like an eternity when he noticed Riku tense, but then he felt Riku’s fingers ghost over his free hand.

Erotic wasn’t a word that normally came to mind when describing Riku as far as Yamato was concerned, but there wasn’t any better fit for the sounds that IDOLiSH7’s center was making as his twin’s tongue danced with his own.  Ten moved one hand from Riku’s cheek and ran it through Riku’s hair to rest it at the back of his head and bring them closer.  Not coherent enough to figure out what to do with his own hands, Riku simply rested them on Ten’s forearms.  A thin thread of saliva stretched between them and snapped once they moved apart.  Their eyes locked in a daze as if they were in a different world.  Ten was the first to recover, and while he didn’t turn away from Riku his eyes moved between his twin and Yamato.  That small movement seemed to break the trance and shortly after Riku was kissing Yamato again.  All of the sweet flavor mostly masked the bitter remnants of alcohol.

Though Yamato couldn’t see the predatory hunger in Ten’s eyes as he was left out to the part of observer, he certainly felt the effects of the frustration when hands slid up his shirt.  He wouldn’t admit out loud that his nipples were a bit sensitive, but the brush of fingertips against them along with the return of warm breath to his ear made Yamato tilt his head back and moan into Riku’s mouth.  Riku used the leverage to move into a more stable position in Yamato’s lap.  Doing so also meant that he felt a firmness against his thigh.  He separated from Yamato and looked down.

“Ah, that’s…” Yamato faltered, too preoccupied with his own feelings of guilt and embarrassment.  He internally panicked a little when Riku moved to stand up, and the only thing holding back and apology was the perplexing presence of a grin on Riku’s reddened lips.  Ten’s hands and mouth stilled at the unexpected movement.  Riku’s back lightly bumped against the table.  The movement made the pudding jar and spoon rattle; the noise was like percussion accompanying their song of uneven breathing.  Without a word, he knelt down between Yamato’s legs.  When he made a move to undo Yamato’s pants, however, his brother’s hand stopped him.

 “Riku, I’ll do it,” Ten said gently.  “You’re inexperienced, right?”

At that question, Riku puffed out his cheeks.  “I do too have experience!” he pouted.

Yamato couldn’t see Ten’s expression from where he was sitting, but he could have sworn he felt a chill.  The momentary silence that followed made the hairs on the back of his neck stand on end.  Then, Ten spoke in a carefully even voice, “When, where, and with whom?”

It was surreal to see someone who was about to give a blowjob scrunch up their face and stick out their tongue childishly, but that’s exactly what Riku did.  “Not telling!”

Any further responses devolved into an argument.  This was something that Ten was not used to.  Apart from when they were too young to understand and know any better, the twins had never fought.  Not up until Ten had left with Kujou.  As much as he couldn’t help but see Riku as the same little brother he had said goodbye to all those years ago, he had been slapped in the face with evidence pointing to otherwise ever since they had met again.  Just how much had changed in those years…?  Or, for that matter, was it even a gradual change?  The only other times he had seen Riku act like this was the occasional times their groups were mashed together for work.  And it was always with a _certain person_.  Decidedly, IDOLiSH7—specifically Izumi Iori—was a bad influence.

As the two continued to bicker, Yamato clenched his fists on the edge of the seat with a slight tremble.  This got worse as the seconds passed by, and he no longer parsed exactly what they were saying, until his knuckles turned white and the shaking finally reached a head and he snapped.  He growled out, “You two…just when I was getting compliant, you stop?!”

Identical wide-eyed expressions were on their faces as Riku and Ten turned to him, as if they had forgotten he was there.  They really did look alike when they were side by side like that, even though they weren’t identical twins.  Yamato let out a sigh of frustration, in various senses of the word.  “Aah, whatever.  I’m going back to bed or something.”

He could have stood up right then and there and put an end to this ludicrous situation.  He could have, _would_ have, but Riku was still holding onto the waistband of his pants and when he went up, they went down, underwear and all.  If Yamato’s face wasn’t completely red before, it definitely was now.  He wasn’t ashamed of his body, but to be seen in this state by someone else, particularly in broad daylight, was embarrassing.  His palm meeting his face wouldn’t make the situation any better, but it was an instinctive reaction.

“Wow…,” Riku whispered, oblivious to Yamato’s internal plight. 

The few inches that Yamato had raised up off the chair were rendered pointless—he collapsed back onto it as soon as he felt Riku’s fingers tentatively grip the base of his erection.  Yamato stared down with his mouth agape.  “Are you seriously going to do this?” he asked incredulously.

Riku tilted his head slightly to one side.  His eyes appeared to be oddly shiny and his lips were formed in the barest indication of a pout.  “Can’t I?”

Yamato heard Ten cough from somewhere behind him.  It seemed neither of them were immune to Riku’s expression.  Yamato was severely tempted to return his hand to his face, for various reasons.  “…Do what you want.”

Those words snapped Ten out of his stupor.  “Hmm, you’ve become rather docile,” he teased.  Yamato scowled at him and told him to shut up.  Ten winked at him and returned to his earlier position.  “Play nice,” he murmured right against Yamato’s ear.

Time seemed to move in slow motion as Riku steadied himself and leaned forward.  He placed a feather-light kiss on the head, and it twitched against his lips.  Moving lower, his mouth opened just enough for his tongue to peek out and slowly slide all the way up from the base to the tip.  The muscle was hot against the sensitive skin, and he shivered at the sensation of the rapidly cooling trail of saliva left behind.  One of Riku’s hands curled into a loose fist at the base.  He took just the tip between his lips and sucked gently.  The feel and sight of it caused all of the air to evacuate Yamato’s lungs.

Not wanting to be left out again, the wet sounds from Ten’s mouth on his ear were as lewd as the ones coming from Riku between his legs.  Yamato shuddered.  He was losing control of the situation again, if he even had any in the first place.  As he felt Riku gradually take more into his mouth, he stopped caring.  He almost whined (Nikaidou Yamato was twenty-two years old, he did not _whine_ ) when Riku’s mouth parted from his member, and he gasped as that tongue played with the slit before sliding under the foreskin.  Yamato’s hands landed in Riku’s hair out of need for something to hold onto.  His fingers shakily massaged circles into the scarlet-hued locks.

A whisper mixed into a hot breath by his earlobe—“Who else has Riku done this with?”

Yamato regained enough composure to turn his head and give Ten a sly smile.  “Sorry.  Onii-san isn’t fond of sharing someone else’s secrets,” he panted out. “Nobody’s asking _you_ to kiss and tell,” then, he let out a hiss, “and biting won’t get it out of me either.  I’m not a masochist.”

“Pity.”

“Are you going to pout?  You’re not as mature as I thought.”

The response from Ten was a snort, before he cupped Yamato’s chin with a surprising gentleness.  They kissed again, longer and deeper than before, and Ten swallowed Yamato’s moans just as his tongue created more of them.  He could feel Ten’s hands slide up his shirt again.  The fingertips were soft against his skin but the dexterity with which they moved made him feel good from spots he didn’t know _could_ be that good.

The wet heat of Riku’s mouth took Yamato’s erection inside again.  That wonderful tongue was pressed flat against the underside.  Slowly, Yamato felt himself slip deeper, deeper, until he could feel the tip hit the back of Riku's throat.  Yamato pushed Ten away from their kiss.  “H-hey, Riku, don’t overdo it.”  While it did feel good to have that much inside, Yamato didn’t want the kid to push himself too far.  Riku’s eyes, which had closed in concentration, opened up, blinked once and curved upwards in a smile.  Then they were shut again, and Riku took a moment to reposition himself.  He brought a hand up to cover one of Yamato’s that were still nestled in his hair, and leaned forward just so.  Yamato inhaled sharply as the last few inches slid down further into Riku’s throat.

“Nnnh…”  Riku quietly moaned from his position on the floor.  The vibrations from it were bliss, and Yamato could swear that his hips were melting.  He couldn’t believe that Riku sounded like he was _enjoying_ having a dick disrupt his breathing.  While it was true that Riku had come to Yamato before for advice in the bedroom, Yamato had always respected his Center’s privacy and never pried into any details.  But the expression on Riku’s face as he began to bob his head suggested that it was the opposite of a problem, and the unbelievable sight made Yamato’s own throat feel suddenly dry.  Riku’s eyes opened briefly once more and he voiced something that sounded suspiciously like “is it good?” but was rendered unintelligible since his mouth was full.  Had Yamato been anything but enthralled with Riku’s mouth, he would have noticed that Ten’s hands had lost a considerable amount of deftness.

Eventually, Yamato noticed that Riku’s fingers were tapping on his hand.  Unsure of what the signal meant, Yamato scrunched his own fingers up in Riku’s hair.  When Riku sucked particularly hard on the way up for air, Yamato groaned and involuntarily pulled Riku’s head back down.  His apology died before it reached his lips when Riku’s fingers stopped tapping and instead rubbed the back of Yamato’s hand, like one would stroke a pet.

No way.

Hesitation and curiosity battled in Yamato’s mind as he curled his fingers into Riku’s hair as gently as possible.  He guided Riku’s head up, allowing a moment for breathing, and then carefully pushed back all the way inside.  Riku hummed around the cock in his mouth and caressed the hands in his hair approvingly.  Yamato swore under his breath and felt precum ooze out into Riku’s mouth.  Unlike with the beer, Riku didn’t seem to mind this taste.  With every stroke of Riku’s tongue and with every push down into Riku’s throat, Yamato had to control himself from bucking his hips up.  While there was a chance now that Riku wouldn’t exactly mind, Yamato couldn’t bring himself to be that rough.  Not with him.

Gradually, the hands guiding Riku’s head became more and more unsteady until Riku took back control and they just rested in the now-tangled hair, leaving Yamato to lean back and lose himself in the pleasure.  The room was dominated by the sounds of three sets of labored breathing (why the hell was _Ten_ panting?) and Yamato had long since given up at holding back his voice.  He felt a telltale pressure building up rapidly in his lower abdomen. 

“Riku,” Yamato warned, “Riku, hurry and pull it out…”  Weakly, he tried to make his hands work again to ease Riku’s mouth off of him, but Riku brushed them off and bobbed his head faster in response to the words.  At the same time, Ten sucked on the ear that he had neglected and pinched Yamato’s nipples between his fingers.  That was too much.  Yamato’s eyes squeezed shut and he let out a cry that was considerably higher than his usual voice.  All at once, the almost painful bubble-like pressure in his abdomen burst, and he shot into Riku’s waiting mouth.  He could feel his back arch more with every bit of come that spurted out of him.  Somewhere in the back of his mind, when he felt Riku’s throat undulate around him one last time, his brain was a loop of “he swallowed he _swallowed heswallowedholyfuck_ ” but he was too spent to process it.  Riku finally relinquished his hold on Yamato’s cock with a wet _pop_ sound.  He licked his lips and rested his head on Yamato’s thigh.  His eyes were glazed over and he coughed once then sighed deeply, content, as if _he_ had been the one to get such a powerful climax.  Yamato also felt Ten’s forehead slump on his shoulder, but only for a moment.

“Well,” Ten said evenly, forcing himself into composure, “it seems you enjoyed our little game more than I anticipated, _Yamato-san_.”  Yamato was too far gone to even process half of the words, let alone figure out what the continued use of his name was supposed to mean.  “It certainly was fun,” Ten continued.  “Maybe I’ll play again sometime.”  Ten raised a hand in acknowledgement, and without another word, he turned around and went straight out the door.

A few seconds later, Riku panted out a bewildered “Wha?” and pushed himself to his feet.  “Wait, Ten-nii!” he called after his brother and dashed after him, not even remembering to put on his shoes.  He sounded out of breath.  Yamato failed to notice that both of them had been walking oddly on the way out.

If anyone was to return home, Yamato was certain to be quite the sight, slumped on a kitchen chair with his pants open and his shirt hiked up.  He blankly stared up at the lights, as if they would answer his questions about what had just happened.  Furthermore, why did Kujou even come here, anyway?  Seriously, why?  The lights didn’t answer.  They just made spots in his vision.

“Ah, Yamato-san,” Riku poked his head back into the dorm.  Through his post-orgasm stupor, Yamato somehow managed to look over at the doorway.  “Actually,” Riku grinned and tapped his own ear, “it’s Iori’s weak point too.”

The sound of the door closing behind Riku was simultaneous with Yamato’s head hitting the table.  He needed a nap.  He needed another shower.


End file.
